1. Field of the Invention
The present invention relates to above ground concrete encased storage tanks and a method for producing the same.
2. Description of Related Art
Metal storage tanks are commonly used to store flammable fluids such as jet fuel. The tanks are typically buried underground to thermally protect the fuel from fire or other combustion means. On occasion the metal containers will leak, wherein the tanks are dug up and repaired or replaced. Excavation is both time consuming and expensive, which has led to the growing use of above ground storage tanks. Above ground tanks are typically encased in concrete to protect the metal containers from fire and other damaging elements.
Manufacturing a concrete encased storage tank, also known as a storage vault, is usually performed by placing the metal container in a form and then pouring concrete around the tank. Because cement is heavier than the tank, the container tends to float upward when surrounded by the concrete. For this reason a method must be incorporated that prevents the tank from floating within the concrete. U.S. Pat. No. 4,826,644 issued to Lindquist et al, discloses a method and apparatus for encasing a storage tank in concrete. The Lindquist method includes an external support device that is placed over the top of the concrete form, wherein the device has support arms that press against the container to prevent the same from floating when concrete is poured around the tank. To encase the tank in concrete, the Lindquist method first creates a support for the tank by pouring a first layer of cement into the bottom of the form. Before the concrete has set, the tank is placed into the form and supported by the first layer of concrete. The external hold down apparatus is placed against the tank and attached to the form. A second layer of concrete is then poured in the form to completely surround the tank.
The Lindquist method is quite time consuming, wherein the support apparatus is both bulky and awkward to install and disassemble. It would be desirable to have a device that prevents the storage tank from floating in concrete that is small and simple to install.